(1) Field of the Invention
The present invention relates to an improvement of the corrosion resistance in the decorative hard golden ceramic article comprising titanium nitride (TiN) or zirconium nitride (ZrN).
(2) Description of the Prior Art
Sintered alloys comprising a carbide, nitride or carbonitride of a transition metal of the Group IV or V, such as TiN, ZrN or TaC, as the main component and a binder metal such as Fe, Co, Ni or Mo has not only a golden hue but also such excellent properties as high hardness and high strength. Accordingly, these sintered alloys are broadly used as decorative articles in order to obtain sintered alloy having high hardness and high strength.
Sintering of TiN, ZrN or TaC alone is very difficult, and therefore, a binder metal as mentioned above is added as a sintering aid. Since the sintering aid is a metal element, corrosion of the metal component present in the sintered alloy is readily advanced, and discoloration is caused, for example, by sweat and the hue of the decorative article is impaired.